Thanks - I had tried both of these and it did not make a difference. I'm happy with Gapped Fade, but there must be some tech difference from MC between the various Switch Track settings for a DAC to care.
That's mighty odd; I've had DACs that clicked on sample rate changes, but those DACs would click no matter which interstitial you chose. I will definitely be attempting to replicate this with my ODAC on Monday, it's truly bizarre (I use aggressive cross-fade or gapless, and haven't ever noticed any clicks, but I haven't been paying attention either).
I would assume that the difference is with the DAC playing silence or simply breaking the connection. (i.e. playing nothing)
I can't think of a reason why playing silence for all of these would be a bad thing.
The thing that makes me wonder about that is that it clicks on gapless or aggressive crossfade, where there is not likely to be a broken connection (i.e. no actual silence). It's a very strange result.